vw_liz
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torbet said:OK, Update 2. It's not good news
Step 3 showed the charging voltage as 12.6. No surprises. But it should be 14v, so the output of the charger is definitely the problem. But what could be causing it???
Step 4 gave me nothing. No reading at all going to the control panel. Now that could be why I am not getting the prongs. It might also be how it is supposed to be on a later model charger, and it only sends the current when the batteries are charged.
Step 5 gives me the same 12.6v.
And step 6 does the same which indicates that it is not a problem with the temp sensor.
I took it apart and it was giving me 700 Ohms which dropped rapidly sat in my palm, so I guess that 500Ohms at 20*C is probably spot on.
The batteries are definitely charging as they were almost flat who I put them in, and now sit at 12.6v unplugged from the mains. I may leave them off the charger for a few days to see if they go flat again. Although I'm not sure if that means they were not fully charged or are not holding a charge.
Not sure what the next step is. Any suggestions?
Good job with the testing and reporting back.
From memory a standing voltage of 12.6v would indicate a fully charged battery but you would need to leave the batteries unconnected to around 24h to measure the standing voltage. The fact that yours measure 12.6v straight after charging says to me they are not fully charged.
Right after a battery has been charging I would expect it to measure much higher (>13v maybe) and drop to the true standing voltage after up to 24hours of no use.
Odd that there is no output on the display line but as you say maybe this is how they suppose to work on later chargers. It also is consistent with the way sidepods works.
It seems that your temperature sensors are working, but I do wonder if maybe later vans use a different value sensor? I have just checked mine and both the battery temperature sensor and the outside temperature sensor are the same part number (357 919 379).
If someone out there has a late t4 westfalia could you check what part number is on your sensor?
It may be that if you put a newer charger on an older van you also should change the sensor?
Next steps? This is what I would do...
First I would try swapping the outside temp sensor with the battery one and see if there is any change to the voltage when on charge. The outside one is very easy to get to, it's just behind the front bumper...
Next I would try heating/cooling the sensor while on charge. Cooling (with ice or a fan?) would probably give the most interesting result as I would expect the output voltage to rise as the resistance increases/sensor gets cooler.
Next I would connect to the mains with the temp sensor removed.....I would expect this to force the charger to output it's maximum charge voltage but do this at your own risk! I personally don't think running the charger without the sensor would cause any short term problems but remember this advise is coming from a man without a westfalia charger so I have no way of knowing what will happen!
Good luck!
Jim
The prongs on the plug appear and disappear at random. I've not yet checked the output voltage of plug 5 to see if that has gone up, but I'm just happy to be able to mains charge.
